The neonatal development of skull morphology is mediated by the dynamic interrelationships between the growing brain, dura mater, and cranial bones. This proposal is directed at identifying relationships which are instrumental in the mechanisms which produce neurocraniofacial deformities associated with craniosynostosis. Permitting normal brain growth, the primary volumetric determinant of skull size, we will mechanically alter growth of the cranial bones (first by premature closure of the suture and second by rapid expansion of the suture) and manipulate the attachments and shape of the dura in order to identify the role these components play in skull growth, the types of dyscephalies they may produce independent of each other, and potential methods for surgical correction of craniosynostosis. Initially, we will use an experimental model which will mechanically induce premature closure of cranial sutures by immobilization of the suture with methyl-cyanoacrylate adhesive. The effects will be monitored roentgenocephalometrically. This will permit us to indentify decephalies which can be attributed directly to premature synostosis, to determine the effects of altered suture growth on growth at other sutures, and to develope an integrated model of the role of cranial sutures in modulating skull growth. The effects of rapid expansion of cranial sutures will be studied by implanation of a distraction spring across the coronal suture at different times during skull growth. The effects will be examined using serial roengtenocephalometry, and LM and EM procedures. In addition, rapid expansion will be applied to prematurely fused sutures following craniectomy of the suture at 30 days of age in order to determine the utility of rapid suture expansion in the treatment of craniosynostosis. The role of the dura mater in premature craniosynostosis is probably the least understood. We will examine the effects of dural manipulation on skull growth. In one group of young rabbits, the dura will be detached from its attachment to crista galli; in a second group, the dura will be detached from the suture per se; and in a third group, the dura will be exposed and plicated. Results will be monitored radiographically, to evaluate the role of dura in skull growth and treatment of synostosis.